JP2670352B2 - Control rod drive water equipment - Google Patents

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial application field) The present invention relates to a control rod driven water equipment used in a boiling water reactor plant.

(Conventional technology) During normal operation, the control rod drive water equipment of a boiling water reactor plant transfers part of the return water from the condensate desalination unit in the condensate supply system to the condensate storage tank in the condensate make-up water system. Securing the amount of water supply to the water pressure control unit during normal extraction and the reactor recirculation pump,
Supply purge water to the reactor coolant purification system pump. Further, at the time of the periodic inspection, the return water from the condensate desalination device stops, so that the water is supplied from the condensate storage tank to the control rod drive water pump. During scram, the required flow rate is insufficient with the amount of water returned from the condensate desalination device, so most of the water is supplied from the condensate storage tank during normal operation and during periodic inspections.

FIG. 3 shows a system configuration of a conventional control rod driving water facility and related condensate makeup water system and condensate water supply system. The condensate make-up water system uses the condensate storage tank 1 as a water source to connect from the condensate make-up water system suction mother pipe 2 to the water supply load 6 using the condensate transfer pump 3 4. Water is supplied through the condensate makeup water system water supply pipe 5. The water supply load 6 includes a main condenser 7, and water supplied to the main condenser 7 is treated by a condensate desalination device 9 through a condensate pipe 8, and then returned to a condensate return pipe. It is a circulation loop that is returned to the condensate storage tank 1 via 10.

Control rod drive water equipment is normally operated and condensate return pipe 10
A part of the return water is taken out by a control rod drive water supply pipe 23 connected to the control rod drive water supply suction pipe 11 and merged into the control rod drive water system suction pipe 11, and then passed through the suction filter 12 to the control rod drive water pump 13
Is transferred to the water pressure control unit and the control rod drive mechanism 15 through the control rod drive water pipe 14 and also via the reactor recirculation pump purge water pipe 16 and the reactor coolant purification system pump purge water pipe 18. Purge water is supplied to the circulation pump 17 and the reactor coolant purification system pump 19.

During normal purge operation, the required flow rate is small compared to the control rod drive water pump 13, so most of the water branches from the control rod drive water pump minimum flow pipe 20 to the control rod drive water heater pipe 21. Then, the circulation operation is performed in which the control rod drive water heater 22 heats the liquid and returns it to the control rod drive system suction pipe 11. This is to prevent dew condensation on the control rod drive water system piping inside the reactor containment, and should be installed on the control rod drive water pump minimum flow pipe 20 if the system water temperature rises too much due to circulation operation. Open the discharge valve 24 to return the hot system water to the condensate storage tank 1.

On the other hand, since the return water from the condensate desalination device 9 stops during the periodic inspection, the water source of the control rod driving water equipment is the condensate storage tank 1 and the control rod connected to the condensate makeup water system suction mother pipe 2. Directly taken out from the drive system suction pipe 11, merged with the control rod drive water system suction pipe 11 as in normal operation, and then transferred to the water pressure control unit and control rod drive mechanism 15 by the control rod drive water pump 13 via the suction filter 12. In addition, purge water is supplied to the reactor recirculation pump 17 and the reactor coolant purification system pump 19 via the reactor recirculation pump purge water pipe 16 and the reactor coolant purification system pump purge water pipe 18. ing.

(Problems to be Solved by the Invention) Generally, the effective suction head of a pump is given by the following equation. Among them, the factors contributing to the plus side are the atmospheric pressure and the hydrostatic head difference. If the required suction lift is large and it is necessary to ensure an effective suction lift, it is necessary to increase the hydrostatic head difference to increase the effective suction lift.

Effective suction lift = Atmospheric pressure-Saturated vapor pressure + Hydrostatic head difference-Piping pressure loss In the case of a control rod drive water pump, the required suction lift of the pump is large and the condensate storage, which is the water source at the time of scram in the pump design mode It is necessary to raise the level of the tank to a certain level to increase the difference in hydrostatic head and increase the effective suction head.

The condensate storage tank of the water source serves as a water source for the condensate transfer pump, high pressure core spray pump, reactor isolation cooling system pump, etc. in addition to the control rod driven water pump, but the required suction lift of the control rod driven water pump is It is the largest and often sets the minimum level for condensate storage. For this reason, as shown in FIG. 4, the condensate storage tank 1 is installed at a high position of the building 30 in which the condensate storage tank is stored. Floor 32
Since the condensate storage tank 1 rises up, it is chased further upward, resulting in a large building volume, which is not favorable in terms of layout and economy.

The present invention has been made to solve the above problems,
Control rod drive that can increase the margin in the design of the condensate storage tank and reduce the volume of the building that houses the condensate storage tank, with the effective suction lift of the control rod drive pump secured as before. To provide water facilities.

[Constitution of the Invention] (Means for Solving the Problems) The present invention connects a condensate auxiliary water supply suction pipe to a condensate storage tank, and connects a condensate transfer pump to the condensate auxiliary water supply suction pipe. Then, a control rod drive water tank is provided at a position higher than the condensate storage tank, a control rod drive water system suction pipe is connected to this control rod drive water tank, and a control rod drive water pump is connected to this control rod drive water system suction pipe. And a control rod driving water pipe are connected.

(Operation) A control rod drive water tank is provided at a position higher than a condensate storage tank where a hydrostatic head difference is sufficient to secure an effective suction lift of the control rod drive water pump, and the control rod drive water tank is used as a water source. Pressurized water is supplied to the water pressure control unit control rod drive mechanism by the control rod drive water pump through the control rod drive water system suction pipe. Since the control rod drive water pump is provided with a more sufficient pushing pressure than before, it is possible to secure an effective suction head given to the control rod drive water pump regardless of the water level in the condensate storage tank.

(Embodiment) An embodiment of the control rod driving water facility according to the present invention will be described with reference to FIGS. 1 and 2. In the figure, the same parts as those in FIGS. 3 and 4 of the conventional example are denoted by the same reference numerals, and the description of the overlapping parts will be omitted.

That is, in the embodiment shown in FIG. 1, the control rod driving water equipment is composed of a condensate storage tank 1 and a condensate return pipe which are conventional water sources.
Rather than receiving water from 10, a dedicated control rod driving water tank 27 is provided at a position higher than the condensate storage tank 1, and water is supplied by the control rod driving water system suction pipe 11 connected to the driving water tank 27.

Specifically, the flow of water is supplied from the control rod drive water tank 27 to the control rod drive pump 13 via the control rod drive water suction pipe 11 and the suction filter 12 regardless of the time of normal operation, regular inspection, and scram. . Its control rod drive water pump 13
The water pressurized by is supplied to the water pressure control unit / control rod drive mechanism 15 connected to the control rod drive water pipe 14, and also the reactor recirculation pump purge water pipe 16 and the reactor coolant purification system pump purge water. Purge water is supplied to the reactor recirculation pump 17 and the reactor coolant purification system pump 19 through pipes 18, respectively.

During normal purge operation, the control rod drive water pump 13
The required flow rate is small with respect to the capacity. Therefore, most of the water is circulated from the control rod drive water pump minimum flow pipe 20 to the control rod drive water heater pipe 21 and returned to the control rod drive water intake pipe 11 while being heated by the control rod drive water heater 22. It is driving. This is to prevent dew condensation on the control rod drive water system piping inside the reactor containment vessel. If the system water temperature is too high due to the circulation operation, the discharge valve 24 installed on the control rod drive water pump minimum flow pipe 20 is opened to return the high temperature system water to the control rod drive tank 27.

Next, the operation around the control rod drive water tank 27 in this embodiment will be described. Return water from the condensate demineralizer 9 is supplied to the control rod drive water tank via the condensate return pipe 10. Similarly, return water from the radioactive waste treatment facility 25 is also supplied to the control rod drive tank 27 via the waste treatment facility return pipe 26.

During normal operation and periodic inspection, the amount of water used in the control rod drive water equipment is very small, and the amount of water entering the control rod drive water tank 27 is larger than the amount of water flowing out. The capacity of the rod drive water tank 27 will be over capacity. Therefore, the overflow level of the control rod drive water tank 27 is provided with an overflow pipe 28, and the transfer destination is the condensate storage tank 1. From this, most of the return water other than the water used in the control rod drive equipment passes through the control rod drive water tank 27 and the overflow pipe 28, and is finally returned to the condensate storage tank as before, The functions of the condensate makeup water system and the high-pressure core spray system using the tank 1 as a water source are maintained as in the conventional case.

Even during the scram, during normal operation, the control rod driving water tank 27 of the water source is supplied with condensate desalination equipment return water more than the required capacity of the control rod driving equipment. The water facility will function as before. In the scrum (O scrum) under periodic inspection, the return water of the condensate desalination device is stopped, but the control rod drive water tank 27 must have a certain capacity and the other water source, radioactive waste treatment Since the facility return water can be expected and the condensate replenishment water system can be replenished by the tank water supply pipe 29, the conventional function can be maintained.

As described above, by installing the control rod drive water tank 27 dedicated to the control rod drive water equipment at a high position, the effective suction lift of the control rod drive water pump 13 becomes sufficiently large, and the condensate storage tank 1 which is a conventional water source is provided. It is possible to operate regardless of the installation level. FIG. 2 shows an outline of a sectional view of a building in which the condensate storage tank 1, the control rod drive water tank 27, the control rod drive water pump 13 and the like are housed in the above embodiment. As is clear from FIG. 2, in this embodiment, the water source is the dedicated control rod drive water tank 27 so as not to be affected by other equipment, and the control rod drive water pump 13 is effective by installing it at a high position. The suction head is sufficiently large. Further, since the restriction on the effective suction lift of the control rod drive water pump 13 is eliminated, the floor height of the condensate storage tank lower floor 31 can be suppressed to a low level by the amount that the installation position of the condensate storage tank 1 can be lowered. .. In addition, the upper floor of the condensate storage tank 1 is moved to the lower position of the condensate storage tank 1.
Since 32 can also move downward, the volume of the building 30 is reduced as a whole and the economy is improved.

[Effects of the Invention] According to the present invention, by providing a dedicated control rod drive water tank, the effective suction lift of the control rod drive pump is maintained in the same manner as in the related art, and condensate storage, which is a conventional water source. There is no connection with the tank. Therefore, there is no restriction on the control rod drive water pump given to the design of the condensate storage tank, the margin is increased in the design of the condensate storage tank, and as a result, the economy of the building which stores the condensate storage tank is reduced. Contribute to improvement.

[Brief description of the drawings]

FIG. 1 is a system diagram showing an embodiment of a control rod driving water system according to the present invention, FIG. 2 is a longitudinal sectional view schematically showing a main building in FIG. 1, and FIG. FIG. 4 is a system diagram showing a control rod driving water system, and FIG. 4 is a longitudinal sectional view schematically showing a main building in FIG. 1 ... Condensate storage tank 2 ... Condensate make-up water intake mother pipe 3 ... Condensate transfer pump 4 ... Condensate make-up water system feed mother pipe 5 ... Condensate make-up water system feed pipe 6 ... Water supply load, 7 …… Main condenser 8 …… Condensation system piping, 9 …… Condensate demineralizer 10 …… Condensation system return piping 11 …… Control rod drive water system suction piping 12 …… Suction filter 13 …… Control rod drive water pump 14 …… Control rod drive water pipe 15 …… Water pressure control unit Control rod drive mechanism 16 …… Reactor recirculation pump purge water pipe 17 …… Reactor recirculation pump 18 …… Reactor coolant purification system pump purge water pipe 19 …… Reactor coolant purification system pump 20 …… Control rod drive water pump minimum flow pipe 21 …… Control rod drive water heater pipe 22 …… Control rod drive water heater 23 …… Control rod drive water supply pipe 24 …… Discharge valve 25 …… Radioactive waste treatment facility 26 …… Waste treatment facility return pipe 27 …… Control rod Dynamic water tank 28 ...... overflow pipe 29 ...... tank water supply pipe 30 ...... building 31 ...... condensate storage tank bottom floor 32 ...... condensate storage tank upper floor

Claims (1)

(57) [Claims] 1. A condensate auxiliary water supply suction pipe connected to a condensate storage tank, a condensate transfer pump connected to the condensate auxiliary water supply suction pipe, and a condensate transfer pump connected to a higher position than the condensate storage tank. Provide a control rod drive water tank, connect the control rod drive water system suction pipe to this control rod drive water tank, and connect the control rod drive water pump and control rod drive water pipe to this control rod drive water system suction pipe. Control rod drive water facility.